The present invention relates to a job processing apparatus for performing jobs in accordance with input job data, and particularly to a job processing apparatus configured to operate in one of operation modes including normal operation mode and power saving operation mode.
In order to reduce power consumption of such job processing apparatuses, it is important to control power supply in period during which no job data is input thereto. In other words, it is necessary to reduce standby power consumption to a minimum level. On the other hands, job processing apparatuses, even during standby time, need to be responsive to external input signal for performing job in accordance with job data input thereto.
Japanese Patent Application Laid-Open No. 2003-228444 discloses a power supply device employing a power control method in which a main power supply section is turned off after a predetermined period of time during which no signal is input thereto. The power supply device said to be responsive to external input signal in the power saving operation mode, because power is supplied, in the power saving operation mode, to a circuit that detects external signal.
The power supply device, however, sometimes unnecessarily switches to the normal operation mode from the power saving operation mode, thereby causing extra power consumption. For example, the power supply device, in the power saving mode, always turns on the main power supply portion upon detection of external input signal relating to job data. But sometimes there exists a situation in which it is not necessary for the power supply device to turn on the main power supply portion for handling external input signal. In such situation, turning on the main power supply portion cause an increase of power consumption.
A feature of the present invention is to offer a job processing apparatus configured to reduce standby power consumption by preventing the main power supply portion from being turned on unnecessarily.